Design Resources: USB 3.1 and Type-C

By: Chris A. Ciufo, Editor, Embedded Systems Engineering

An up-to-date quick reference list for engineers designing with Type-C.

USB 3.1 and its new Type-C connector are likely in your design near-future. USB 3.1 and the Type-C connector run at up to 10 Gbps, and Type-C is the USB-IF’s “does everything” connector that can be inserted either way (and never is upside down). The Type-C connector also delivers USB 3.1 speeds plus other gigabit protocols simultaneously, including DisplayPort, HDMI, Thunderbolt, PCI Express and more.

Also new or updated are the Battery Charging (BC) and Power Delivery (PD) specifications that provide up to 100W of charge capability in an effort to eliminate the need for a drawer full of incompatible wall warts.

If you’ve got USB 3.1 “SuperSpeed+” or the Type-C connector in your future, here’s a recent list of design resources, articles and websites that can help get you up to speed.

Start Here: The USB Interface Forum governs all of these specs, with lots of input from industry partners like Intel and Microsoft. USB 3.1 (it’s actually Gen 2), Type-C, and PD information is available via the USB-IF and it’s the best place to go for the actual details (note the hotlinks). Even if you don’t read them now, you know you’re going to need to read them eventually.

“Developer Days” The USB-IF presented this two-day seminar in Taipei last November 2015. I’ve recently discovered the treasure trove of preso’s located here (Figure 1). The “USB Type-C Specification Overview” is the most comprehensive I’ve seen lately.

Figure 1: USB-IF held a “Developer Days” forum in Taipei November 2015. These PPT’s are a great place to start your USB 3.1/Type-C education. (Image courtesy: USB-IF.org.)

Figure 1: USB-IF held a “Developer Days” forum in Taipei November 2015. These PPT’s are a great place to start your USB 3.1/Type-C education. (Image courtesy: USB-IF.org.)

What is Type-C? Another decent 1,000-foot view is my first article on Type-C: “Top 3 Essential Technologies for Ultra-mobile, Portable Embedded Systems.” Although the article covers other technologies, it compares Type-C against the other USB connectors and introduces designers to the USB-IF’s Battery Charging (BC) and Power Delivery (PD) specifications.

What is USB? To go further back to basics, “3 Things You Need to Know about USB Switches” starts at USB 1.1 and brings designers up to USB 3.0 SuperSpeed (5 Gbps). While the article is about switches, it also reminds readers that at USB 3.0 (and 3.1) speeds, signal integrity can’t be ignored.

USB Plus What Else? The article “USB Type-C is Coming…” overlays the aforementioned information with Type-C’s sideband capabilities that can transmit HDMI, DVI, Thunderbolt and more. Here, the emphasis is on pins, lines, and signal integrity considerations.

More Power, Scotty! Type-C’s 100W Power Delivery sources energy in either direction, depending upon the enumeration sequence between host and target. Components are needed to handle this logic, and the best source of info is from the IC and IP companies. A recent Q&A we did with IP provider Synopsys “Power Where It’s Needed…” goes behind the scenes a bit, while TI’s E2E Community has a running commentary on all things PD. The latter is a must-visit stop for embedded designers.

Finally, active cables are the future as Type-C interfaces to all manner of legacy interfaces (including USB 2.0/3.0). At last year’s IDF 2015, Cypress showed off dongles that converted between specs. Since then, the company has taken the lead in this emerging area and they’re the first place to go to learn about conversions and dongles (Figure 2).

Figure 2: In the Cypress booth at IDF 2015, the company and its partners showed off active cables and dongles. Here, Type-C (white) converts to Ethernet, HDMI, VGA, and one more I don’t recognize. (Photo by Chris A. Ciufo, 2015.)

Figure 2: In the Cypress booth at IDF 2015, the company and its partners showed off active cables and dongles. Here, Type-C (white) converts to Ethernet, HDMI, VGA, and one more I don’t recognize. (Photo by Chris A. Ciufo, 2015.)

Evolving Future: Although USB 3.1 and the Type-C connector are solid and not changing much, IC companies are introducing more highly integrated solutions for the BC, PD and USB 3.1 specifications plus sideband logic. For example, Intel’s Thunderbolt 3 uses Type-C and runs up to 40 Gbps, suggesting that Type-C has substantial headroom and more change is coming. My point: expect to keep your USB 3.1 and Type-C education up-to-date.